Introduction: This report details the steps taken and processes used to discover the identity of the unknown organism given on Tuesday, November 28th, 2017. With all of the knowledge and skills gained over the semester, in class and in lab, unknown organism 6C was able to be positively identified. The objective of these labs was to successfully utilize the tests and procedures taught during the course to correctly identify the organism and to be able to explain the reasoning behind the tests used and results found. Procedures: On the first day of the lab, an unknown bacteria was presented. The sample of the bacteria was labeled simply as 6C. First, the colony morphologies of the bacteria were observed. It was circular in form, raised in elevation, …show more content…
The urease hydrolysis test was used to detect the production of urease and ultimately ammonia which urease produces. The urease test was conducted by inoculating the slant of the agar. If urease was produced it would hydrolyse urea and create ammonia which would increase the pH and turn the agar hot pink. Therefore, a positive urease test would have a color change to hot pink agar, whereas a negative urease test would have no color change and the agar would remain its original color. The last test performed to assist in determining the identity of the unknown bacteria was a citrate utilization test. This test was chosen to determine if the unknown organism could use citrate as its sole carbon and energy source. It was completed by inoculating the slant of Simmons citrate agar and allowing access to oxygen. A positive result would include a color change in the agar from green to blue, due to the utilization of citrate causing an increase in pH. A negative result would not include a color change in the agar, it would remain …show more content…
Capsule stains are used to detect if the bacteria can produce a capsule. A capsule is a thick layer outside of the cell wall that protect the bacteria from leukocytes and helps with the bacteria's ability to invade its host. A capsule stain was performed using Congo red, acid-alcohol, and acid fusion along with a smear of the bacteria. A positive would result in the ability to see a capsule surrounding the bacteria. A negative would result in only seeing the bacteria and no capsule around it. Results and Discussion: The gram stain was negative. The bacterial cells observed under the microscope were pink in color from the safranin stain, but all traces of the crystal violet were washed away with the alcohol wash. The bacterial cells were observed to be small and bacillus or rod shaped. The MAC plate test was negative. Though the color of the agar changed from pink to yellow, the color bacterial colonies was unchanged. Rather than pink colonies, there were white colonies growing on the plate. The ornithine decarboxylase test was negative. Though the results were rendered invalid by being left to incubate over the weekend, it was determined and then confirmed that the test was negative. The bacteria could not produce decarboxylase. This caused the medium to medium to remain acidic and be yellow in
Table 6 shows the results of the biochemical tests. The isolate can obtain its energy by means of aerobic respiration but not fermentation. In the Oxidation-Fermentation test, a yellow color change was produced only under both aerobic conditions, indicating that the EI can oxidize glucose to produce acidic products. In addition to glucose, the EI can also utilize lactose and sucrose, and this deduction is based on the fact that the color of the test medium broth changed to yellow in all three Phenol Red Broth tests. These results are further supported by the results of the Triple Sugar Iron Agar test. Although the EI does perform fermentation of these three carbohydrates, it appears that this bacterium cannot perform mixed acid fermentation nor 2,3-butanediol fermentation due to the lack of color change in Methyl Red and Vogues-Proskauer
What do bacteria need to grow? For bacteria to grow the most typical thing that they like ate a warm and moist environment, but that is not all that they like. Bacteria also like and environment with a PH that is normal or close to a human PH and bacteria also like an oxygen rich environment. The places that could be common to find bacteria in a building are a keyboard, a water fountain, and restrooms. A keyboard is a common place for bacteria because it is being touched constantly with hands when people type and hands are warm, so bacteria like them. The water fountain is another place that is common for bacteria to grow because people's warm hands are touching it and also it has water, which causes it to be moist. The last place that bacteria will we commonly found in buildings are restrooms. The bacteria like restrooms because many people are in then and also there is a lot of water in them.
One bacterium was gram negative. It underwent four different tests. These tests were the EMB test (Eosin Mehylene Blue), the Sulfur Indole Motility (SIM) test, the Urease test, and the Simmon’s Citrate Utilization test. The EMB test checks for a bacteria’s ability to ferment lactose. This test is accomplished by placing the bacteria on Eosin Methylene Blue agar. The agar is selective for gram negative bacteria and those bacteria that can ferment lactose will have colored growth, usually a metallic green sheen.
Streak plate technique was used to isolate pure culture for each bacteria (2). The Gram stain was used to determine Gram reaction and morphology of each bacteria (2) Selective and differential media such as, salt agar, MacConkey agar and blood agar were used for bacterial identification (2). Gelatin deeps were inoculated to detect production of gelatinase (2). Starch Agar plate were inoculated to detect amylase (2). Ocular reticle used to determine bacteria size (2). Motility deeps were inoculated to detect motility on bacteria (2). Thioglycollate broth used to determine oxygen requirements (2). Carbohydrate fermentation
These biochemical tests are process of elimination that relies on the bacteria’s ability to breakdown certain kinds of food sources, their respiratory abilities and other biochemical conditions found in nature. The results of these tests prove that the unknown organism is Citrobacter freundii hereby referred to as C. freundii. C. freundii is a member of the Enterobacteriaceae family, like all the other unknowns given in this test. The species is a facultative anaerobic and is a gram-negative bacilli.
I also inoculated a tryptic soy broth (TSB), a nutrient gelatin deep, a motility agar deep, a fluid thioglycollate medium (FTM) tube, and a TSA plate with my unknown culture. All of these inoculated media were incubated until the next class period (about 48 hours). Then when I came to class most of my inoculated tubes and my streak plate appeared to have growth. The next step I took was making a gram stain to determine the gram reaction and cellular morphology of my unknown. I used my working slant to do this, after careful examination of the gram stain, I learned that my unknown was a gram-positive bacterium. I then preceded by making a negative stain to see the size of the cells of my unknown bacteria. The cell shape was cocci and the cells occurred in clusters of tetrads. After discovering that my unknown bacteria was gram-positive cocci, I turned to page 207 of the lab manual to narrow down my options, there was only four out of the gram-positive list that were
The purpose of this project was to identify unknown bacteria species from a mixed culture. The two unknown species were initially plated onto Tryptic Soy Agar (TSA), Eosin Methylene Blue (EMB), Mannitol Salt Agar (MSA), and blood agar plates to distinguish between the two different bacteria using colony size, color, shape, and growth characteristics. By identifying and inoculating the differing types of colonies, the two unknown bacteria were purified and able to be tested
Discussion: This particular enzyme assay in question employs the optimal techniques/materials in order to achieve the highest amount of precision in the assay process. As urease is a soil enzyme and is actively involved in the breakdown of urea the release of its products, ammonia and carbon dioxide, are direct indicators of its concentration and activity
This is because the cells are normally stained with Gram's iodine solution which forms a complex with crystal violet stain that is insoluble in water. Addition of decolourizer dehydrates the peptidoglycan layer; tightening it and shrinking peptidoglycan layer of the gram positives, making the large complex not penetrate the layer. When a counter stain is added, it does not disrupt the complex i.e. purple colouration of the Gram positive cells. Therefore, in absence of Gram's iodine solution, the Gram positive cells would stain brownish red as gram negative cells, making it difficult for the identification of the unknown bacteria (Leboffe and Pierce, 2010). 13. (2 points) Control slides are missing in The Gram Stain Investigation. What are they and what is their importance in the straining
I identified the genus and species of an unknown bacterial culture, #16, and I applied the following knowledge of morphologic, cultural and metabolic characteristics of the unknown microorganism according to the laboratory manual as well as my class notes and power point print outs. I was given an incubated agar slant labeled #16 and a rack of different tests to either examine or perform myself; the tests are as follows: Gram Stain; Nutrient Gelatin Test; Carbohydrate Fermentation; Dextrose, Lactose and Sucrose; IMVIC tests; Citrate, Indole, Mythel-Red and Vogues Proskauer test; as well as a Urease and TSI Test. Materials and Methods/Results Upon receiving the Microorganism (M.O.) #16, I prepared a slide by cleaning and drying it. Then, using a bottle of water I placed a sterile drop of water on the slide and used an inoculating loop, flame sterilized, I took a small sample of the unknown growth in my agar slant and smeared it onto the slide in a dime sized circle and then heat fixed it for ten minutes.
In the last decade, the number of prescriptions for antibiotics has increases. Even though, antibiotics are helpful, an excess amount of antibiotics can be dangerous. Quite often antibiotics are wrongly prescribed to cure viruses when they are meant to target bacteria. Antibiotics are a type of medicine that is prone to kill microorganisms, or bacteria. By examining the PBS documentary Hunting the Nightmare Bacteria and the article “U.S. government taps GlaxoSmithKline for New Antibiotics” by Ben Hirschler as well as a few other articles can help depict the problem that is of doctors prescribing antibiotics wrongly or excessively, which can led to becoming harmful to the body.
Bacterial cells, like plant cells, are surrounded by a cell wall. However, bacterial cell walls are made up of polysaccharide chains linked to amino acids, while plant cell walls are made up of cellulose, which contains no amino acids. Many bacteria secrete a slimy capsule around the outside of the cell wall. The capsule provides additional protection for the cell. Many of the bacteria that cause diseases in animals are surrounded by a capsule. The capsule prevents the white blood cells and antibodies from destroying the invading bacterium. Inside the capsule and the cell wall is the cell membrane. In aerobic bacteria, the reactions of cellular respiration take place on fingerlike infoldings of the cell membrane. Ribosomes are scattered throughout the cytoplasm, and the DNA is generally found in the center of the cell. Many bacilli and spirilla have flagella, which are used for locomotion in water. A few types of bacteria that lack flagella move by gliding on a surface. However, the mechanism of this gliding motion is unknown. Most bacteria are aerobic, they require free oxygen to carry on cellular respiration. Some bacteria, called facultatibe anaerobes can live in either the presence or absence of free oxygen. They obtain energy either by aerobic respiration when oxygen is present or by fermentation when oxygen is absent. Still other bacteria cannot live in the presence of oxygen. These are called obligate anaerobes. Such bacteria obtain energy only fermentation. Through fermentation, different groups of bacteria produce a wide variety of organic compounds. Besides ethyl alcohol and lactic acid, bacterial fermentation can produce acetic acid, acetone, butyl alcohol, glycol, butyric acid, propionic acid, and methane, the main component of natural gas. Most bacteria are heterotrophic bacteria are either saprophytes or parasites. Saprophytes feed on the remains of dead plants and animals, and ordinarily do not cause disease. They release digestive enzymes onto the organic matter. The enzymes breakdown the large food molecules into smaller molecules, which are absorbed by the bacterial cells. Parasites live on or in living organisms, and may cause disease. A few types of bacteria are Autotrophic, they can synthesize the organic nutrients they require from inorganic substances. Autotrophic bacteria are either photosynthetic or Chemosynthetic. The photosynthetic bacteria contain chlorophyll that are different from the plant chlorophyll. In bacterial photosynthesis, hydrogen is obtained by the splitting of compounds other than water.
Isolation of bacteria includes several techniques by which different bacterial colonies from a mixed culture can be separated. This isolation is important as it helps in studying the particular organism with its distinguished traits. Bacteria are in habit of living in an association with other organism/bacteria as this association will help in the better survival of an organism. These microbial populations will cooperate together and achieve better nutrients for each other because the waste of one may serve as a nutrient for the other. Similarly the waste from the metabolism of the one may provide the favourable condition to the other for growth.
stains on sputum’s and body fluids, and have completed a few AFB cultures. Apart from